


when morning comes we'll be safe

by bestcarrot



Category: Haikyuu!!
Genre: Alternate Universe - Fantasy, Demon Slayer: Kimetsu no Yaiba Manga, M/M, no one dies I promise
Language: English
Status: Completed
Published: 2020-04-23
Updated: 2020-04-23
Packaged: 2021-03-01 16:41:34
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,785
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23800246
Author URL: https://archiveofourown.org/users/bestcarrot/pseuds/bestcarrot
Summary: Sakusa is on a mission to kill the demon that lurks in the abandoned shrine.
Relationships: Miya Atsumu/Sakusa Kiyoomi
Comments: 18
Kudos: 195





	when morning comes we'll be safe

There is a village far off the beaten path, surrounded by tall stalks and even taller mountains. In the winter, the snow would pile on the roofs of straw-thatched huts. When the frost melts away, the grasses would grow green once again, bright with life, butterflies dancing to the tune of spring. When the nights turn warm and sticky, the summer brings its ghosts and childish games and glowing paper lanterns, strung along the shrine grounds like trails of fire.

And when the trees finally burn crimson, and the harvest moon hangs high in the sky, the benevolent god that resides at the Inari shrine comes out to play.

Or so the village elders once said. Nowadays, there are less fairytales and more stories of missing villagers. The husband who never returned from the fields, the wife thought to have slipped and fell into the river, the baby who was snatched from its crib. Nowadays, the village elders say to the naughty children, ‘Do not play outside in the night, lest you disturb the sleeping god with your noise. For if you anger a god, he will surely come to claim your soul.’ The fairytales never truly go away.

The village elders speak to a swordsman clad in black uniform. ‘Do not come near the abandoned shrine. A sleeping god rests there.’

The swordsman, by the name of Sakusa Kiyoomi, ignores their warning and steadily climbs the stone steps to the shrine. He neither fears nor believes in the presence of such a lazy god.

The wind brushes against the trees, raining leaves over the shrine grounds. A bell-tree tinkles lightly in the distance. Sakusa enters through the red torii gate, his sheer white haori billowing from his back, saintly and pristine.

The shrine is guarded by dead branches and stone statues that have been worn down through the years. Paper lanterns still cling onto the fences, torn and lightless as they are. Half-rotting leaves scatter along the stone walkway that leads into a dilapidated house. A faint burning smell wafts through the air. Sakusa frowns, though it is hidden behind the war mask that completely covers the lower half of his face.

“Come out, foul beast. I know you’re in there,” Sakusa says, soft and muffled. At the absence of a response, he clicks his tongue and draws his katana in one fluid motion. The blade, black as its user’s heart, blends seamlessly into the shadows of night.

“If you’re not coming, then I’ll drag you out myself. What will it be?”

Sakusa waits, brows knitting together as he listens for the sounds of floorboards creaking. A light chuckle echoes from the shrine’s hall of worship, and a pair of predator eyes stare out from the dark room, pupils glowing in vertical slits.

Emerging from its desecrated altar, the demon—not a god—meets Sakusa’s holy figure, bathed in moonlight.

“My, oh my. And here I was just havin’ a good dream.”

The demon Atsumu yawns, sharp canines peeking out of his lips. His kimono hangs loosely around him, one arm out of its sleeve to reveal a chiseled torso, tougher than steel.

“Two years.” Sakusa breathes, deep and steady. “I waste two years tracking down every scent, every trail left by you and your disgusting hide—only to end up in a dump like this. Figures.”

Atsumu snickers. A bushy fox’s tail briefly flickers into sight.

“Well, well, well—thanks very much for your hard work, Mr. Pillar of the Demon Slaying Corps. If I’d known you were coming, I would’ve cleaned the place up a little. Make it fit fer worship, ya know? S’a shrine, after all.”

A wooden placard chooses to fall from the shrine’s wall in that moment, kicking dust into a cloud.

“No one would come to worship at this godforsaken place.”

“‘Godforsaken’ ya say? But m’right here.” Atsumu perks, his face contorting into a dangerous grin. “Go on, don’t be shy. I’ll hear ya out fer a prayer or two. M’feelin’ charitable tonight.”

Sakusa is in no mood for this.

“You’re a demon, Miya—”

Fox ears twitch at the faintest sounds—the wingbeats of a dragonfly, the rush of water from the nearby falls. Loudest of them all is the careful, measured breathing of the swordsman who stands before him, tall and serene in one moment, and prepared to strike the very next. Atsumu grins wider.

“—And I’m not here to pray.”

“Tha’s right."

The autumn wind blows colder in the night. From a distance, the shrine bells chime in a lonely tune. Sakusa points his sword with the words branding the blade, _Destroy all evil demons,_ their one guiding truth in this cruel, cruel world.

Atsumu makes the first move. A sphere of fox fire explodes between them, scattering gold-tinged flames that consume everything in its path. Sakusa nimbly dodges the blast, his footsteps light and quick. He happens to land on a pile of detritus he suspects is a person's corpse. The permanent scowl on his face somehow doubles in intensity.

Summoned from the pits of hell itself, the gaping, fiery maw charges at Sakusa.

“Turn ta dust,” Atsumu drawls, keenly watching as the swordsman makes no move to run.

Within seconds, the fire is extinguished, slashed apart by a force not unlike a roaring tide.

“Oh?”

Sakusa resumes his initial stance, and his blade almost appears to glimmer with a damp sparkle. His techniques are works of art, made with strength and elegance in every stroke. He unleashes another attack, this time a single, downward slash that carries the weight of a cascading torrent. His sword comes up empty, the ground underneath pulverized into rubble.

Someone claps from the far side.

“Wow,” Atsumu whistles impressed, “even I hafta admit—that was beautiful. I think you jus’ captured my heart right then an’ there—"

Another slash, three more, and Sakusa’s sword barely catches the tip of a kimono sleeve. Sakusa hears a hearty laugh, followed by the whoosh of claws cutting through air. The visage of a wild animal flashes before his eyes, its large jaws aiming straight for his jugular.

Sakusa crouches at the last minute, countering with another attack. It leaves him open for a fraction of a second, and a clawed hand springs for his neck. He briefly thinks he might die; in this line of work, the thought has crossed his mind more times than he cares to count. There’s the sound of something breaking, like a vase splitting into two. He manages to pull himself away with his throat still intact.

Atsumu snickers. The deep gash across his stomach heals instantly.

“Ya dropped somethin’ o’yours.”

The neck guard falls to pieces at Sakusa’s feet. His half-mask goes next, cracked right across the center. Blood drips from the cut on his lower lip.

“A lesser man would’ve gotten his throat torn out right then an’ there,” Atsumu remarks, admiring the sharp points of his fingertips. When he catches Sakusa’s dark gaze, his mouth curls into a wild grin.

Sakusa’s lungs fill with air, sending sure strength to his limbs. Fox fire chases him from one point to another. A statue burns bright in the night. Sakusa extinguishes them all with a single swing, and the maple leaves shudder from the sudden gust.

“I like ya,” Atsumu pushes back on the blade barehanded, “wha’s yer name, _handsome_?”

His smug tone grates on Sakusa’s nerves. Sakusa hates it. Sakusa hates him—this demon that’s murdered countless of innocents, ruined the lives of so many, and continue to take and take and take until nothing is left. Sakusa hates that feral look, that inhuman strength, the hideous mouth that never shuts up.

Most of all, he hates that Atsumu doesn’t even bother to remember.

The distance between them has grown. Sakusa presses a hand on his bleeding shoulder. The blood soaks through his haori, a blooming patch of red against white gossamer threads.

“Gotta say, ya put up a great fight.” Atsumu licks the blood from his wrist. “Prolly the best one I’ve ever had the pleasure of knowin’.”

Sakusa remains silent, determined to deny the demon his conversation.

“Aw, c’mon,” Atsumu gripes. “Will it kill ya to say somethin’ back? At this rate, I’m gonna hafta beat the words outta ya, and there’s no turnin’ tail once I get serious.”

Right then, Atsumu draws his own gold-tinged sword from its hilt. The air around him shifts. He swings wildly with the intent to devour his opponent, the swordplay of a raging beast, except his form retains a certain cunning edge. Sakusa sees it as nothing else but techniques honed from years of combat.

“Huh. Ya don’t look so surprised t’see a demon using Breaths.”

“It’s not as uncommon as you might think,” Sakusa answers flatly. He knows of one other demon that used Breaths before they learned to slaughter humans indiscriminately. Another Corps member turned into the very thing they swore to annihilate.

“Really, now? An’ here I thought I was special.”

“You’re a disgrace, Miya, so do us all a favor and die already.”

“That’s cold of ya.” Atsumu huffs a short laugh. “S’that how you talk to a former comrade? I don’t even know who ya are.”

Sakusa throws a small explosive that does not detonate—instead, it unfurls into a net trap woven from wisteria blossoms. The net burns under fox fire. Sakusa is already onto his next attack, making slash after slash. His steps ripple into one another, flowing and flowing like a great river current, cold and unforgiving.

“Don’t you hold yerself back on me now,” Atsumu yells through the sound of steel clashing together. “You’re a pillar of the Corps, aren’t cha? If ya want me dead, yer gonna hafta try a lot harder than that!”

Sakusa gets blasted all the way into the empty shrine halls. Buried under the planks, he feels a throbbing pain in his chest. He is paralyzed. While he lies there, the dust enters his lungs, contaminating his blood stream, tainting him from the inside out and he wants to get away before everything makes him sick to his bones.

“I never said I was a pillar,” Sakusa coughs out, trying not to breathe too hard. His ragged voice carries an accusation recognizable only to the demon standing at the shrine’s threshold.

“Doesn’t take a genius ta figure it out, what with the annoying way you move.”

“You called me a pillar even before we began crossing swords.” Sakusa rises from the caved-in walls. His haori ripped to shreds, clinging to his shoulders like a spider’s web. “It must feel vaguely familiar to you. This sword, this scenery, this fight. What does it all remind you of?”

For once, Atsumu does not immediately speak. Clutching the handle of his blade, he stares back into the dark, where a man he once knew stands bleeding out of his skin. That flicker of hesitation, however small, must count for something.

Atsumu lunges in for the kill. The look on his face belongs to someone who no longer cares.

It takes Sakusa everything he has to withstand the next attack. His katana breaks into two. Facing what appears to be imminent defeat, Sakusa pulls out his reserve weapon—the smaller wakizashi—coated in wisteria poison. He dodges Atsumu’s attacks as if it were all part of an intricate dance, and the performance ends with a stab that stings like a spider’s bite.

“How’s that fer a surprise!” Atsumu is gleeful despite his veins visibly convulsing from the poison’s effects. “I knew you were special. Not a lot of Corps members use more than a single Breath style in combat. They tend to rely on whichever one suits ‘em best, but you jus’ gotta have ‘em all, huh, Mr. Talented!”

 _Not true_ , Sakusa thinks distantly, while he gets kicked back to the floor. The wakizashi falls dangerously close to his face. Above him, Atsumu bathes in his own flames, burning the toxins away. His voice echoes in Sakusa’s ear—"Shoulda used a stronger poison, shoulda aimed for the vitals.” Shoulda done this, shoulda done that. If Sakusa was so talented, if Sakusa was so strong with his two Breath styles and his impressive pillar status—then why, why, why couldn’t Sakusa save Atsumu, back then? Why couldn’t he stop the demons from abducting Atsumu? Why had he not been there when Atsumu was hurt and alone? Why couldn’t he have been a good friend?

Why can’t he save the person most important to him?

“I don't get it. Why can’t you jus’ kill me? I’m a demon. Yer job is to slay demons. Isn’t that how things are supposed to be?

“S’it because we used to be friends? I don’t remember any of it. Not unless I dream about ‘em, in my sleep. None of it feels real, but I must’ve seen your face in there somewhere, too.

“It drives me crazy jus’ thinkin’ about it. Because even when you’re right here glarin’ at me like mad, I still can’t remember your name, fer god’s sake.”

_But I remember yours._

Sakusa has fought harder battles with more serious injuries, but the pain in his body is unbearable at this point. The exhaustion built over the past two years finally catches up. He is tired of killing, tired of being powerless. His hand wants for his blade.

“Get up,” Atsumu says. “Get up an’ fight.”

Sakusa is so tired, but he didn’t come here to destroy more things.

“If you’re thinking I’d let you order me around, then the demonification must have completely rotted out your already pea-sized brain.”

“‘Scuse you, my brain is bigger an’ better than yours will ever be!”

Taking up the wakizashi, Sakusa makes his final charge. He forces Atsumu back outside—back to where they started, underneath the moonlit sky.

A strong gust passes through Sakusa’s airways, and the power returns to his limbs. His gaze is razor sharp. Atsumu’s expression twists into a maniacal smile. Hovering within arm’s length of each other, they are both about to deliver finishing blows. Sakusa’s technique proves superior, and Atsumu’s sword flies out of his grasp.

Then Sakusa is holding a syringe. He has one shot of the antidote, and nothing else. He baits Atsumu into putting down all his defenses to ensure the greatest chance of success. This whole time, he has been waiting for the best opportunity to strike.

Atsumu is the faster of the two. He drives his claws deep, deep, deep. The ground is on fire, painted crimson red. Fox ears shiver at the sound of a name, spoken in hushed breaths, like a precious secret.

“ _Atsumu_.”

The needle plunges into his bare chest, straight into the heart. And that’s when he finally remembers.

“Omi…kun?”

A brush of wind sends red autumn leaves fluttering from above. A maple leaf lands on dark, sweat-slicked curls. Sakusa slumps to the ground, broken but not defeated. His breath stutters.

“Omi-kun,” Atsumu whimpers like a wounded animal, “Omi-kun. Omi-kun!"

Atsumu retracts his arm through the gaping hole he made on a shrine statue. Shards of stone fall on top of Sakusa’s head. Atsumu drops to his knees and extends a shaky hand out. His fingers, rough and calloused, brush the grit off and linger along the side of Sakusa’s face.

“You remembered.”

He did. He remembered at just the right moment and redirected his attack at the very last second, before everything could end in tragedy.

“‘Course I would. M’a smart guy, Omi-kun. You know that better than anyone else.” Atsumu starts to cry for the first time in a long, long while.

“Piece of shit.”

Atsumu makes a disgusting noise with his snot-filled nose, and Sakusa closes his eyes to spare himself the view. Sakusa is simply resting after a hard-fought win. He is not trying to hold back the flood of tears threatening to spill any second now.

“Fuck, Omi-kun, yer bleedin’ all over!”

“And whose fault is that?”

“We gotta get ya to a doctor, like, right now—”

“Shut up. I’m trying to sleep.”

“No, wait! Don’t you dare die on me now, Omi-kun! Yer not allowed ta go before me!”

Atsumu wails like a child. Sakusa has to pry his eyes open just to show that no, he is not going to die, and Atsumu doesn’t have to endure a life of loneliness. The sun will rise and they will be okay.

Sakusa sits up and presses his forehead to Atsumu’s. Just to feel the warmth from Atsumu’s face. He feels this and so much more, when the dawn finally breaks, and the light pours over them both.

“Let’s go home.”

**Author's Note:**

> I had so much fun! This was VERY self-indulgent. I chose to go with water pillar!Sakusa x fox demon!Atsumu this time, but there's a ton of other cool possibilities in the kny realm it's so amazing!! Lemme know what u think in the comments :' )


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